Latch devices



K. A. W. KEMP LATCH DEVICES Aug. 11, 1970 Filed Jan. 6-, 1969 2Sheets-Sheet 1 INVE TOE f medgfiz/w XW ATTOEN EYS Aug. 11, 1976 K. A. w.KEMP 3,523,457

LATCH DEVICES Filed Jan. 6, 1969 2 Sheets-Sheet 2 BYD v ATTZ SEN EYSUnited States Patent 01 lice 3,523,457 Patented Aug. 11, 1970 3,523,457LATCH DEVICES Kenneth Albert Walters Kemp, Ealing, London, England,assignor to C.A.V. Limited, London, England Filed Jan. 6, 1969, Ser. No.789,185 Claims priority, applicati tligz/Gg'seat Britain, Jan. 5, 1968,

Int. Cl. G05g 17/00 US. Cl. 74-2 5 Claims ABSTRACT OF THE DISCLOSURE Alatch device of the kind intended to retain a resiliently loaded memberin a first position, the latch device comprising a first member whichextends into the path of the member, a second member telescopicallyengaged with the member, and movable between first and second axialpositions, the arrangement being that as the member is moved from itsfirst to its second position the member will telescope relative to themember and as the latter is returned to its first position the frictionbetween the two members will cause the member to be moved out ofengagement with the resiliently loaded member.

This invention relates to latch devices of the kind intended to retain aresiliently loaded member in a first position, the latch device whenoperated serving to permit said member to move to a second positionunder the action of its resilient loading.

The object of the invention is to provide such a latch in a simple andconvenient form.

According to the invention a latch device of the kind specifiedcomprises a first member extending into the path of said resilientlyloaded member, a second member telescopically engaged with said firstmember and movable between first and second axial positions, thearrangement being such that as the second member is moved from its firstto its second position the first member will telescope relative to thesecond member and as the latter is returned to its first position thefriction between the two members will cause the first member to be movedout of engagement with the resiliently loaded member thereby allowingthe latter to move to its second position.

In the accompanying drawings:

FIGS. 1 and 2 illustrate in sectional side elevation, two examples oflatch devices in accordance with the invention. The latch devicestherein illustrated are intended to control the setting of the fuelcontrol rod of a liquid fuel pumping apparatus. The fuel control rod isindicated at in the drawings and as shown particularly in FIG. 1 it isresiliently loaded by means of a coiled compression spring 11 in thedirection to increase the quantity of fuel which is supplied by theapparatus. In this position shown the control rod is set to provide thenormal maximum quantity of fuel. For starting purposes it is well knownthat an excess of fuel is required but it is essential to ensure thatthis excess should not be obtainable by the driver of the vehicle whenthe vehicle is in normal use.

Referring now to FIG. 1 the latch device comprises a first member 12which is of stepped cylindrical form. The narrower end portion of thismember extends through an aperture formed in the body of the device andinto the path of the free end of the fuel control rod 10. The firstmember is accomodated with a small degree of clearance within a boreformed in a second member 13 slidable in the body part of the device.The second member is loaded in an outward direction towards a firstposition, by means of a coiled compression spring 14 and actingintermediate the first and second members is a light coiled compressionspring 15. In the position shown in FIG. 1 the control rod 10 applies aforce to the member 12'to cause the later to tilt within the bore of themember 13. When excess fuel is required the member 13 is moved to asecond position against the action of the springs 14 and 15 and when itis allowed to return to its first position under the action of thespring 14 the friction developed primarily at the two points of contactof the members 13 and 12 is suflicient to cause the member 12 to followthe movement of the member 13. When this occurs the narrower end of themember 12 is moved out of the path of the control rod 10 and the lattermoves under the influence of its spring 11 to a position in which anexcess of fuel is supplied to the engine and with the end of the member12 bearing on this side of the rod.

When the associated engine has been started the governor of the pumpingapparatus will move the control rod 10 to reduce the quantity of fuelsupplied to the engine. As soon as this occurs the member 12 is moved bythe light spring 15 to a position to block movement of the control rodto the excess fuel position. The operating knob of the member 13 is outof the reach of the operator of the vehicle and therefore when thevehicle is in use on the road it is impossible to actuate the device toobtain an excess of fuel.

A modified form of the device is seen in FIG. 2 and parts having thesame function are provided with the same reference numerals. It will beapparent that the spring 14 has been omitted so that the member must bemoved by hand to its first position. It will be seen also that the bodyportion 16 of the device is adjustably mounted relative to the body ofthe pumping apparatus and in this manner variations of the setting ofthe control rod in the maximum fuel position can be obtained. Inaddition it will be noted that a stop 17 is provided and adjustment ofthis stop enables the position of the control rod 10 in the excess fuelposition to be adjusted.

It will be appreciated that when the engine has started even if theoperating knob of the member 13 is held in its innermost position thenexcess fuel will not be obtained once the control rod 10 has been movedout of the path of the member 12 since the latter will immediatelyassume its blocking position to prevent further supply of excess fuel.

Having thus described my invention what I claim as new and desire tosecure by Letters Patent is:

1. A latch device of the kind intended to retain a resiliently loadedmember in a first position, the latch device when operated serving topermit said member to move to a second posiiton under the action of itsresilient loading, the device comprising a first member extending intothe path of said resiliently loaded member, a second membertelescopically engaged with said first member and movable between firstand second axial positions, the arrangement being such that as thesecond member is moved from its first to its second position the firstmember will telescope relative to the second member and as the latter isreturned to its first position the friction between the two members willcause the first member to be moved out of engagement with theresiliently loaded member thereby allowing the latter to move to itssecond position.

2. A latch device as claimed in claim 1 including resilient means actingbetween the members in a direction to urge the members apart.

3. A latch device as claimed in claim 2 including further resilientmeans acting to urge the second member towards its first position.

4. A latch device as claimed in claim 2 including adjustable stop meanswhereby the second position of the resiliently loaded member can beadjusted.

5. A latch device as claimed in claim 4 including means for adjustingthe position of the first and second members relative to a body mountingsaid resiliently loaded mem- 'ber whereby the first position of theresiliently loaded member can be adjusted.

MILTON KAUFMAN, Primary Examiner US. Cl. X.R.

